Jian-Ping Wang, a materials physicist from the University of Minnesota in Twin Cities, and his colleagues have produced a material that is 18% more magnetic than the most magnetic material known to this day. They have been able to produce a combination of eight parts iron, one part nitrogen. The resulted material has the formula Fe16N2 and its extremely high magnetism lies in its complicated crystalline structure.
X-ray probing showed that in Fe16N2 each nitrogen atom sits in the center of a cluster of six iron atoms and that a couple more iron atoms sit between neighboring clusters. The electrons flowing between the clusters act much like electrons in ordinary iron. But the electrons in the iron atoms in the clusters tend to get stuck, or “localized,” where they are. As a result, Wang says, those atoms contribute more like individual atoms to the overall magnetism, driving it way up.
Research done in 1972 by other scientists had already discovered that Fe16N2 has unusual magnetic properties. Those mathematical assumptions had been confirmed in the 1990s by Hitachi, but at those times some of the results depended on tricky estimations of exactly what fraction a sample’s volume consisted of Fe16N2, which is metastable and tends to fall apart into other crystal structures. Others have not been able to reproduce the Hitachi results, says Eric Fullerton, a physicist at the University of California, San Diego.
Wang’s team has been perfecting its techniques for several years and now they can successfully grow samples of Fe16N2. The new material’s magnetism has been measured with a technique called “X-ray magnetic circular dichroism”, which compares the material’s ability to absorb x-ray light whose polarization twirls to the right or to the left.
The discovery of a magnetic material 18% stronger than anything yet known would have remarkable effects on many industries, including energy generation, electric motors, alternators, and even super-efficient, super-small and ultra-high capacity hard drives. And even on those magnetic motors that some try to talk about.